"In the early part of this year, March or April, we saw for the
first time in many years a decline in absolute numbers for steel
production in China, and that's reflected through now into the
import levels for coal and iron ore, and the shipping rates,
which are associated with those types of ships."

In other words, you can compare raw shipping figures from places
like Baltic Exchange with that of the Chinese government, and
deduce what it says about imports and exports.

Penn added that China's shipping growth slowed down for the first
time in 12 years without giving specific figures.

The Baltic Dry
Index, a measure of shipping that is heavily dependent on the
strength of China imports, is at a 1 month low, according to
Bloomberg:

The Baltic Dry Index, which tracks the movement of raw materials,
fell to its lowest level since 1985 earlier this year, while the
index was 43 per cent weaker than the previous year.

Part of this is down to China, which has turned away from coal
towards cleaner energy sources. And a more general slowdown in
the country’s economy has led to a reduction in imports of
materials like iron.